Screen structure for comminuting apparatus



MarCh 1965 E. T. KOCH, JR., ETAL 3,237,753

SCREEN STRUCTURE FOR COMMINUTING APPARATUS 4 Sheets-Sheet 1 Filed March 20, 1963 Y 00 m m TK H 0 g MW E M March 1, 1966 E. T. KOCH, JR, ETAL 3,237,763

SCREEN STRUCTURE FOR COMMINUTING APPARATUS Filed March 20, 1963 4 Sheets-Sheet 2 INVENTORS 2 EDMqka 7. Koch; J6, JHMES R. M088 A ORNEY March 1, 1966 E. T. KOCH, JR., ETAL 3,237,763

SCREEN STRUCTURE FOR COMMINUTING APPARATUS 4 Sheets-Sheet 5 Filed March 20,

INVENTORS: E n mo 7. Koch; J16, JAM )ES R. M0 8 ORNEY March 1966 E. T. KOCH, JR, ETAL 3,237,768

SCREEN STRUCTURE FOR COMMINUTING APPARATUS Filed March 20, 1963 4 Sheets-Sheet 4 JHMES Moss oRNEY United States Patent 3,237,768 SCREEN STRUCTURE FOR CflMMlNUTiNG APPARATUS Edward T. Koch, J12, Goodlettsville, and James R. Moss,

Springfield, Tenn, assignors to Seco, lino, Goodlettsville, Tenn, a corporation of Tennessee Filed Mar. 20, 1963, Ser. No. 266,575 2 Claims. (ill. 209-453) This invention relates to screen structure, and more particularly to an apparatus for changing screens for classifying comminuted material.

Heretofore in the art of classifying comminuted material, and particularly in the classifying of comminuted material discharged from a hammer mill, single screen panels of various sizes have been interchangeably employed in the discharge opening of the hammer mill. Thus, Where different sizes of comminuted materials are desired, the hammer mill must be shutdown while the individual screen panels are interchanged. In grain milling, a single hammer mill is employed for grinding different kinds of grain, such as barley, corn, oats, so that many different sizes of ground grain are desired. In order to accommodate the various sizes, an individual screen panel for each size is maintained in stock so that the various panels may be interchanged as desired. However, the manual interchanging of these individual panels requires a certain amount of labor time, plus the shutdown time of the machine. Such time-consuming practices result in considerable inefliciency in the processing of the grain and the operation of the hammer mill.

It is therefore an object of this invention to overcome the above disadvantages by providing a novel screen structure for automatically interchanging screen panels in a minimum of time and without shutting down the material processing equipment, such as a hammer mill.

One object of this invention is to provide a unitary screen structure incorporating the desired number of screen panels in series and means for shifting the unitary structure to register the desired panel with the classifying station or discharge opening of the comminuting apparatus.

Another object of this invention is to provide an elongated unitary screen structure incorporating a series of screen panels of uniform dimensions but having progressively different size openings and means for reciprocating the structure beneath the discharge opening of a hammer mill for registering any single panel with the openmg.

Another object of this invention is to provide a movable r screen structure having a series of screen panels of different size openings, and novel control means for reciprocating the screen structure.

A further object of this invention is to provide a novel apparatus for changing screen panels of different sizes in a hammer mill, and novel means for locking each panel in registry with the discharge opening of the hammer mill.

Another object of this invention is to provide an automatic screen changer for a hammer mill which may be rapidly and efficiently operated to change and lock screen panels in their operative positions in a minimum of time and without shutting down the hammer mill.

Further objects and advantages of the invention will be apparent from the following description taken in conjunction with the drawings, wherein:

FIG. 1 is a perspective view of a hammer mill incorporating the invention;

FIG. 2 is a fragmentary top plan view of the hammer mill and the invention disclosed in FIG. 1, with parts broken away;

FIG. 3 is a section taken along the line 3-3 of FIG. 2, with parts broken away;

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FIG. 4 is a section taken along the line 4-4 of FIG. 2;

FIG. 5 is a section taken along the line 55 of FIG. 4, with a portion of the screen structure broken away;

FIG. 6 is a section taken along the line 66 of FIG. 5, disclosing a fragment of the screen structure.

Referring now more particularly to the drawings, a typical hammer mill 10 is disclosed having a housing 11 including a rotary chamber 12 receiving a rotary shaft 13 carrying a plurality of hammers 14. The shaft 13 is driven by a pair of motors 15 and 16 supported on a stationary frame 17. The upper portion of the housing 11 is provided with an inlet 19 receiving a chute 20 to carry coarse material, such as whole grain to be discharged into the rotary chamber 12. The coarse material or grain is ground to a size determined by the openings in the screen structure 22 which closes the discharge opening 24 in the rotary chamber 12, and then deposited in a receiving chamber 25. The grain is then drawn through the conduit 26 by suction means, such as the fan 27, and discharged through the outlet pipe or nozzle 28 to a receptacle or conduit, not shown.

The screen structure 22 is an elongated unitary structure having a uniform arcuate cross-section adapted to conform to the same arcuate configuration of the bottom edges of the end walls 30 and 31 of the housing 11, having arcuate band seats 32, which define the discharge opening 24 and seat against the screen structure 22 in locked position. The screen structure 22 is substantially longer than the discharge opening 24 and is divided into a plurality of screen panels 33, 34 and 35 of equal dimensions such that each panel may register with the discharge opening 24 for classifying the comminuted grain ground in the rotary chamber 12 by the hammers 14. Each screen panel 33, 34 and 35 contains a plurality of screen openings or mesh 36, 37 or 38, respectively, of uniform size, but the mesh in each screen panel is of different size from the mesh in any other screen panel. For example, FIG. 2 discloses the screen panel 33 having large uniform size openings 36; screen panel 34 has intermediate uniform size openings 37; and screen panel 35 has small uniform size openings 38. The screen panels 33, 34 and 35 may be constructed from a single sheet of arcuate material, such as metal, by forming the respective size holes 36, 37 and 38 in the single sheet of material to form the unitary screen structure 22. The unitary screen structure 22 may also be formed by constructing each panel 33, 34 and 3S individually and then securing the panels in successive and adjacent end to end abutting relationship, by Welding or by any other convenient securing means.

A first cradle 40 and a second cradle 41 are fixedly mounted on the frame 17 on opposite sides of the hammer mill housing 11. A third or intermediate cradle 42 is mounted beneath the discharge opening 24. Each cradle 40 and 41 comprises a plurality of longitudinally spaced transverse arcuate members 44 connected by a plurality of longitudinal members or beams 45 and 45. The intermediate cradle 42 includes a pair of end plates 47 and 48 having arcuate upper surfaces, concave upward, and connected by longitudinal members or beams 49. The cradles 40, 41 and 42 are longitudinally aligned so that the arcuate surfaces of the transverse members 44 and the end plates 47 and 48 will conform to and slidably support the arcuate screen structure 22. Fixed to the opposite outer surfaces of the screen structure 22 are a pair of longitudinal runners 50 adapted to slide along the beams 45 of the cradles 4t and 41 (FIG. 3) and through the slots 51 in the end plates 47 and 48 of the cradle 42 (FIG. 4).

The end plates 47 and 48 are also provided with openings 53 and 53 for rotatably receiving eccentric cams 54 and 54' affixed to rotary shafts 55 and 55' rotatably supported in stationary journals, not shown. The shafts 55 and 55 are connected to the upper ends of the crank arms 56 and 56, the lower ends of which are pivotal'ly linked by the arm 57. A lever 58 is also connected to the shaft 55 and is pivotally connected by a pin 59 to a piston rod 60 adapted to be reciprocated in the hydraulic cylinder 61 pivotally mounted at 62 on the frame 17. The hydraulic cylinder 61 is double-acting and supplied with fluid through the lines 63 and 64, which are alternately supplied with hydraulic fluid from the control panel 65 through the valve 66. Thus, it is seen that by manipulating the valve 66, hydraulic fluid is introduced into the cylinder 61 to withdraw the piston rod 60 to rotate the shafts 55 and 55' in the direction of the arrow disclosed in FIG. 4 to elevate the intermediate cradle 42 and the screen structure 22 to firmly seat the screen structure 22 against the arcuate end walls 30 and 31. This operation completely closes the discharge opening 24, except for the screen openings 36, 37 or 38 and locks the appropriate screen panel 33, 34 or 35 in position for classifying the material comminuted by the hammer mill.

The mechanism for reciprocably moving the screen structure 22 to its various longitudinal positions beneath the housing 11 is best disclosed in FIGS. 1 and 2. This mechanism comprises a hydraulic cylinder 68 mounted adjacent the housing 11 and having its longitudinal axis substantially parallel to the longitudinal axis of the screen structure 22. The cylinder 68 is double-acting and communicates through the fluid lines 69 and 70 with the valve 71 on the control panel 65. By manipulating the handle 71, hydraulic fluid may be fed into the cylinder 68 on either side of the piston, not shown, supporting piston rods 73 and 7 4 extending longitudinally from the opposite ends of the cylinder 68. The free ends of the piston rods 73 and 74 support freely rotatable pulleys or sheaves 75 and 76, respectively. A pair of pulleys 77 are supported to rotate about vertical axes on the left end of the frame 17, and a second pair of pulleys 78 are similarly mounted to rotate about vertical axes on the right end of the frame 17. A first cable 79 is fixed at one end by any convenient means, such as the loop 80 extending through an opening in the left end of one of the runners 50. The cable then passes around the pulleys 77, the piston rod pulley 75, and is fixedly connected at its opposite end by means such as an eye bolt 82 to a portion of the frame 17.

In a like manner, a second cable 85 is fixed at one end by a loop 86 extending through an opening in the opposite end of the same runner 81. The cable 85 likewise passes around the pulleys 78 and the piston head pulley 76, and is connected at its opposite end by means of an eye bolt 87 to a fixed part of the frame 17.

Thus, it will be seen that the hydraulic cylinder 68 may be actuated by the valve 71 to move the piston rods 73 and 74 as a unit either to the right or to the left, thereby moving the screen structure 22 in the opposite direction, namely to the left or to the right, respectively. It will also be observed that the piston head pulleys 75 and 76 and the eye bolts 82 and 87 give the hydraulic cylinder 68 and piston rods 73 and 74 a mechanical advantage of two to one so that the screen structure 22 may be moved longitudinally twice as far as is necessary to move either piston rod. The hydraulic valve 71 may be manipulated until the desired panel 33, 34 or 35 registers with the discharge opening 24, either by sight alignment, or by any other convenient type of indexing means.

In operating the invention, screen structure 22 is initially unlocked, that is, lowered to the position disclosed in FIG. 3, by manipulating the valve 66 so that the hydraulic cylinder 61 Will urge the piston rod 60 upward to rotate the shafts 55 and 55' in a counter-clockwise direction. With the screen structure 22 unlocked, the valve 71 may then be manipulated to move the screen structure 22 in either longitudinal direction until the appropriate screen panel, for example 35, is in vertical alignment or registry with the discharge opening 24 in the bottom of the housing 11, as disclosed in FIG. 2. Since the dis- 431. closed screen panel 35 incorporates the smallest screen openings 38 in the screen structure, then very fine ground material will be obtained.

With the screen structure 35 in proper registry, the valve 66 is then manipulated to withdraw the piston rod 69 into the cylinder 61, thereby counter-rotating the shafts 55 and 55 in a clockwise direction, as disclosed in FIG. 4, in order to cause the eccentric earns 54 and 54' to move in their respective holes 53 and 53 and thereby elevate the cradle 42 to force the screen structure 22 upward against the arcuate edges of the end walls 30 and 31. Thus, the discharge opening 24 is sealed, except for the screen openings 38. The motors 15, 16 and the suction fan 27 are then started to drive the hammer mill and grind the whole grain or other solid materials introduced into the housing 11 through the chute 2% The comminuted material is then discharged through the screen openings 38 into the receptacle 2 5 and through the suction fan 27 to the outlet 28.

Even while the hammer mill is in operation, the screen structure 22 may be unlocked by actuating the valve 66, as previously described, and the screen structure may be longitudinally moved to a position registering the screen panel 34 with the discharge opening 24, as illustrated by the phantom-line position 22 in FIG. 2, or to register the screen panel 33 with the discharge opening 24 in the position indicated by phantom-line 22" in FIG. 2. After the screen structure has been moved to its desired position, the valve 66 is again moved in the opposite direction to lock the screen structure 22 in position, as previously described.

Thus, it will be apparent that the screen structure 22 and its controls provide a mechanism for quickly and efficiently changing screens, but also for quickly changing the screens Without shutting down the hammer mill. It is, of course, within the scope of this invention to provide any number of screen panels in the unitary screen structure 22, which are needed and which can be effectively controlled.

It Will be apparent to those skilled in the art that various changes may be made in the invention without departing from the spirit and scope thereof, and therefore the invention is not limited by that which is shown in the drawings and described in the specification, but only as indicated in the appended claims.

What is claimed is:

1. An apparatus for classifying comminuted material, comprising:

(a) a housing for receiving said material having first and second opposed end walls,

(b) said end walls having bottom edges comprising longitudinally aligned arcuate seats defining a discharge opening therebetween,

(c) a first elongated cradle having an arcuate cross section stationarily mounted adjacent the outside of said first end wall, and longitudinally aligned, but spaced slightly below said arcuate seats,

(d) a second elongated cradle stationarily mounted adjacent the outside of said second end wall, said second cradle being longitudinally aligned with and having the same arcuate cross section as said first cradle,

(e) an intermediate cradle having the same arcuate cross section as said first and second cradles, and mounted longitudinally between said first and second cradles and beneath said discharge opening,

(f) a unitary screen structure longer than said intermediate cradle, and having the same arcuate cross section as said arcuate seats and said intermediate cradle,

(g) said screen structure comprising a plurality of longitudinally aligned screen panels, each panel being individually adapted to register with said discharge opening,

(h) means for vertically moving said intermediate cradle from a lower open position where said screen structure is supported for longitudinal movement upon at least two adjacent cradles, to an upper closed position where said screen structure is elevated above said first and second cradles and snugly fitted against said arcuate seats to close said discharge opening, except for the openings in said screen structure, and (i) means for longitudinally moving said screen structure over said cradles in open position to register any one of said panels with said discharge opening. 2. The invention according to claim 1 further comprising elongated runners mounted on the bottom of said screen structure, means on said intermediate panel for slidably receiving said runners, and means on said first and second cradles for supporting said runners for longitudinal movement thereof.

References Cited by the Examiner UNITED STATES PATENTS Mansfield 209-253 Carlson 60S2 Hughes 209281 Calkins 24189 Humphrey 24189 Torjes 209-314 Gruendler 24189 HARRY B. THORNTON, Primary Examiner.

HERBERT L. MARTIN, Examiner. 

1. AN APPARATUS FOR CLASSIFYING COMMINUTED MATERIAL, COMPRISING: (A) A HOUSING FOR RECEIVING SAID MATERIAL HAVING FIRST AND SECOND OPPOSED END WALLS, (B) SAID END WALLS HAVING BOTTOM EDGES COMPRISING LONGITUDINALLY ALIGNED ARCUATE SEATS DEFINING A DISCHARGE OPENING THEREBETWEEN, (C) A FIRST ELONGATED CRADLE HAVING AN ARCUATE CROSS SECTION STATIONARILY MOUNTED ADJACENT THE OUTSIDE OF SAID FIRST END WALL, AND LONGITUDINALLY ALIGNED, BUT SPACED SLIGHTLY BELOW SAID ARCUATE SEATS, (D) A SECOND ELONGATED CRADLE STATIONARILY MOUNTED ADJACENT THE OUTSIDE OF SAID SECOND END WALL, SAID SECOND CRADLE BEING LONGITUUDINALLY ALIGNED WITH AND HAVING THE SAME ARCUATE CROSS SECTION AS SAID FIRST CRADLE (E) AN INTERMEDIATE CRADLE HAVING THE SAME ARCUATE CROSS SECTION AS SAID FIRST AND SECOND CRADLES, AND MOUNTED LONGITUDINALLY BETWEEN SAID FIRST AND SECOND CRADLES AND BENEATH SAID DISCHARGE OPENING, (F) A UNITARY SCREEN STRUCTURE LONGER THAN SAID INTERMEDIATE CRADLE, AND HAVING THE SAME ARCUATE CROSS SECTION AS SAID ARCUATE SEATS AND SAID INTERMEDIATE CRADLE, 